copyright©2000 by houghton mifflin company. all rights reserved. 1 section 10.5 carbon & silicon:...

Download Copyright©2000 by Houghton Mifflin Company. All rights reserved. 1 Section 10.5 CARBON & SILICON: NETWORK ATOMIC SOLIDS NETWORK SOLIDS: SOLIDS CONTAINING

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  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Section 10.5 CARBON & SILICON:NETWORK ATOMIC SOLIDSNETWORK SOLIDS:SOLIDS CONTAINING STRONG DIRECTIONAL COVALENT BONDS TO FORM A SOLID THAT MIGHT BE BEST VIEWED AS A GIANT MOLECULE

    EXAMPLE:DIAMOND AND GRAPHITE

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 10.22The Structures of Diamond and Graphite

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *DIAMONDHARDEST NATURALLY OCCURING SUBSTANCE

    ELECTRICAL INSULATOR

    C ATOM COVALENTLY BONDED BY OVERLAP OF sp3 HYBRID ORBITALS

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 10.22The Structures of Diamond and Graphite

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *GRAPHITESLIPPERYBLACKELECTRICAL CONDUCTORLAYERS OF C ATOMS STRONGLY BONDED TO 3 OTHERS THROUGH sp2 HYBRID ORBITALWEAK BONDING BETWEEN LAYERS BY UNHYBRIDIZED 2p ORBITALS TO FORM DELOCALIZED BOND ELECTRICAL CONDUCTIVITY

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 10.24The p OrbitalsSee also Figure 10.25.

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *SILICONIMPORTANT CONSTITUENT OF COMPOUNDS THAT MAKE UP EARTHS CRUST

    SILICAFUNDAMENTAL COMPOUNDA SILICON OXYGEN COMPOUNDEMPIRICAL FORMULA: SiO2 BUT ACTUALLY NETWORK OF SiO4 TETRAHEDRA

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 10.26The Structure of Quartz

    Si at the center of tetrahedral arrangement with 4 oxygen atoms.

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *SILICATESSIMILAR SiO4 TETRAHEDRA AS SILICA HOWEVER O/Si RATIO > 2:1

    CONTAINS SILICON-OXYGEN ANIONS

    ALSO CONTAIN CATIONS TO BALANCE NEGATIVE CHARGE

    SILICATES ARE SALTS

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 10.27Silicate Anions

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 10.28Two Dimensional Representations of (a) a Quartz Crystal and (b) a Quartz Glass Glass is an amorphousSolid - melt silica then cool rapidly.

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *GlassSubstances are added to common glass to alter its properties.

    See Table 10.5.

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *CERAMICSMADE FROM CLAYS (CONTAIN SILICATES)

    HARDENED BY FIRING AT HIGH TEMP.

    EXCELLENT STABILITY AT HIGH TEMP.

    RESISTANT TO CORRISION

    HOWEVER BRITTLE

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *SemiconductorsElemental Silicon has same structure as diamond. (Both in Group 4A)

    Diamond is insulator due to large energy gap between filled & unfilled Molecular Orbitals.

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 10.23Partial Representation of the Molecular Orbital Energies in A) Diamond and B) a Typical Metal

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *SEMICONDUCTORSELEMENTAL SILICON HAS SMALLERGAP BETWEEN FILLED AND UNFILLEDMOLECULAR ORBITALSAT ROOM TEMP, A FEW e1- CANCROSS THE GAP PROVIDINGSEMICONDUCTIVITYAS TEMP , MORE e1- AREEXCITED AND CONDUCTIVITY

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *DOPINGCONDUCTIVITY OF SILICON ENHANCEBY DOPING Si CRYSTALS WITHOTHER ELEMENTSTWO TYPES:1) n-TYPE SEMICONDUCTORS2) p-TYPE SEMICONDUCTORS

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *n- TYPE SEMICONDUCTORREPLACE SMALL FRACTION OF SiWITH ATOMS LIKE ARSENIC (As)EACH HAVING ONE MORE Ve1- THAN SiEXTRA e1- s AVAILABLE FORCONDUCTION

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *p- TYPE SEMICONDUCTORSi DOPED WITH ATOMS HAVING FEWER Ve1- s

    CREATES HOLESELECTRON MOVES TO FILL THE HOLE,CREATING NEW HOLE

    PROCESS IS REPEATED

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 10.29Silicon Crystal Doped with (a) Arsenic and (b) Boron N-typeP-type

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 10.30Energy Level Diagrams for (a) an n-Type Semiconductor and (b) a p-Type Semiconductor

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *p-n JUNCTIONCONNECTION OF p-TYPE AND n-TYPEMOST IMPORTANT APPLICATIONOF SEMICONDUCTORS

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *Figure 10.31The p-n Junction

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *RECTIFIERDEVICE THAT PRODUCES A PULSATING DIRECT CURRENT (i.e., FLOWS IN ONLY ONE DIRECTION)

    FROM ALTERNATING CURRENT (i.e.,FLOWS IN BOTH DIRECTIONS ALTERNATELY.

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

  • Copyright2000 by Houghton Mifflin Company. All rights reserved. *REVOLUTIONIZED ELECTRONICS!!p-n JUNCTION TRANSMITS CURRENT ONLY UNDER FORWARD BIAS

    CONVERTS ALTERNATING CURRENT TO DIRECT CURRENT

    Copyright2000 by Houghton Mifflin Company. All rights reserved.

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